A microwave susceptor typically comprises a layer of metallized plastic film laminated to a dimensionally stable substrate, such as paperboard. The thickness of the metal is such that the metal absorbs microwave energy and converts it into heat. Such susceptors are commonly used commercially to brown and crispen food in contact with the susceptor. One example of such use is in connection with frozen, packaged pizza having a diameter of about 7 inches (about 18 cm). The susceptor, which is placed under the pizza, browns and crispens the crust of the pizza. However, it has been found that a conventional susceptor does not brown or crispen the center of the pizza satisfactorily when the pizza has a diameter from about 8 to 12 inches (about 20 to 30 cm). U.S. Pat. No. 4,896,009 to Pawlowski discloses that the browning and crisping effect of a susceptor used with pizzas having diameters between 7 and 12 inches can be improved by providing one or more apertures at the center of the susceptor. According to Pawlowski, the improvement is due to the escape of vapor through the apertures, which allows the pizza to remain in contact with the susceptor. However, providing apertures in the susceptor requires a separate step in the manufacture of the susceptor and produces chad that must be disposed of. It also destroys the integrity of the susceptor, which forms part of the package for the pizza.
This invention provides a susceptor that produces results at least as good as the results produced by the susceptor in Pawlowski by providing a pattern of microwave transparent areas in the susceptor. U.S. Pat. Nos. 4,883,936 and 5,220,143 disclose that the heating effect of a susceptor can be reduced in selected areas by providing a pattern of microwave transparent areas in the susceptor, but the object of this invention is to increase, not reduce, the heating effect of the susceptor. U.S. Pat. No. 5,530,231 discloses that the heating effect of a susceptor can be increased by providing a pattern of microwave transparent areas in the susceptor, but the patent fails to teach the pattern of this invention, which produces superior results.